Vibration attenuation system for electric and hybrid electric vehicles

Abstract

In some examples, an aircraft comprises an airframe, a rotor system coupled to the airframe, and a vibration attenuation system. The rotor system is operable to exert a vibratory force on the airframe. The vibration attenuation system comprises two or more batteries and elastic devices. The two or more batteries are operable to supply power to the rotor system. The elastic devices coupled to the two or more batteries and the airframe. The elastic devices are configured to attenuate the vibratory force based on facilitating oscillation of the two or more batteries. In other examples, a method comprises coupling elastic devices to two or more batteries and an airframe of an aircraft. The elastic devices receiving a vibratory force via the airframe and attenuate the vibratory force based on facilitating oscillation of the two or more batteries.

What is claimed is: 
     
       1. An aircraft comprising:
 an airframe; 
 a rotor system coupled to the airframe, the rotor system being operable to exert a vibratory force on the airframe; and 
 a vibration attenuation system comprising:
 first and second batteries to supply power to the rotor system; 
 a first elastic device coupled between a first surface of the first battery and to the airframe; and 
 a second elastic device coupled between a first surface of the second battery and the airframe; 
 
 wherein each of the elastic devices is configured to attenuate the vibratory force based on facilitating oscillation of the one of the batteries to which the elastic device is coupled; and 
 wherein the first elastic device has a stiffness tuned to a first frequency and the second elastic device has a stiffness tuned to a second frequency based on respective locations of the first and second batteries along a length of a fuselage of the aircraft. 
 
     
     
       2. The aircraft of  claim 1 , wherein:
 the first elastic device of the elastic devices supports the first battery at a location along a length of the airframe, the location corresponding to a local maximum displacement of a normal mode of the airframe. 
 
     
     
       3. The aircraft of  claim 1 , wherein each of the elastic devices is configured with a stiffness to facilitate the batteries oscillating at a particular frequency, wherein the particular frequency attenuates the vibratory force within a threshold range of a natural frequency of the airframe. 
     
     
       4. The aircraft of  claim 3 , wherein the threshold range comprises ±30% of the natural frequency of the airframe. 
     
     
       5. The aircraft of  claim 1 , wherein a stiffness of at least one of the elastic devices is constant. 
     
     
       6. The aircraft of  claim 1 , wherein a stiffness of at least one of the elastic devices is variable. 
     
     
       7. The aircraft of  claim 1 , wherein the elastic devices comprise one selected from the group consisting of: a mechanical spring, an elastomeric spring, a gas spring, and a variable stiffness spring. 
     
     
       8. The aircraft of  claim 1 , wherein each of the batteries comprises an electric-vehicle battery. 
     
     
       9. A vibration attenuation system comprising:
 first and second batteries to supply power to a rotor system of an aircraft; and 
 a first elastic device coupled between a first surface of the first battery and to an airframe of the aircraft and a second elastic device coupled between a first surface of the second battery and the airframe of the aircraft, the elastic devices being configured to attenuate a vibratory force of the airframe based on facilitating oscillation of the more batteries, wherein the first elastic device has a stiffness tuned to a first frequency and the second elastic device has a stiffness tuned to a second frequency based on respective locations of the first and second batteries along a length of a fuselage of the aircraft. 
 
     
     
       10. The vibration attenuation system of  claim 9 , wherein each of the elastic devices is configured with a stiffness to facilitate the batteries oscillating at a particular frequency, wherein the particular frequency attenuates the vibratory force within a threshold range of a natural frequency of the airframe. 
     
     
       11. The vibration attenuation system of  claim 10 , wherein the threshold range comprises +/−30% of the natural frequency of the airframe. 
     
     
       12. The vibration attenuation system of  claim 9 , wherein the elastic devices comprise one selected from the group consisting of: a mechanical spring, an elastomeric spring, a gas spring, and an adjustable variable stiffness support. 
     
     
       13. The vibration attenuation system of  claim 9 , wherein each of the batteries comprises:
 a battery management system comprising a housing, wherein the battery management system is operable to monitor the battery and manage an operating temperature of the battery. 
 
     
     
       14. A method comprising:
 coupling a first elastic device to a first battery and an airframe of an aircraft; 
 coupling a second elastic device to a second battery and the airframe of the aircraft; 
 receiving, by the elastic devices, a vibratory force via the airframe; and 
 attenuating, by the elastic devices, the vibratory force based on facilitating oscillation of the batteries, wherein the first elastic device has a stiffness tuned to a first frequency and the second elastic device has a stiffness tuned to a second frequency based on respective locations of the first and second batteries along a length of a fuselage of the aircraft. 
 
     
     
       15. The method of  claim 14 , further comprising:
 oscillating, by the batteries, at a particular frequency based on a stiffness of one or more of the elastic devices, wherein the particular frequency attenuates the vibratory force within a threshold range of a natural frequency of the airframe. 
 
     
     
       16. The method of  claim 15 , wherein the threshold range comprises +/−30% of the natural frequency of the airframe. 
     
     
       17. The method of  claim 14 , further comprising:
 suspending, by the elastic devices, the batteries from top surfaces of the batteries. 
 
     
     
       18. The method of  claim 14 , wherein supporting, by the elastic devices, the batteries at bottom surfaces of the batteries.